Between 2005 and 2009, Colorado used 1.5 million gallons of fracking fluid. That puts the state at number two in the nation according to a report by the House Energy and Commerce Committee. This has raised concerns about what chemicals are in the fluid, and if they affect drinking water.

Fracking, or hydraulic fracturing, pumps chemicals into oil reservoirs to increase the recovery rate. A nationwide investigation of 14 major oil and gas companies recently found that most fracking fluid contains a number of chemicals--some of them harmless, like gelatin, and some of them harmful, like carcinogenic benzene.

Authorities can demand disclosure of these chemicals, and some companies voluntarily submit the information to a statewide online database. The chemical contents of fracking fluids, though, are not public record.

State regulators have questions about how these chemicals may be affecting drinking water. Local environmental groups, along with House representatives, are now seeking disclosure requirements on fracking fluids in order to answer these questions.